Propagation of Sound
Pp. 62-119 (58)
Magnus Wahlberg and Ole Næsbye Larsen
As an acoustic signal travels from the source to a receiver, it is affected by a
variety of physical processes, all dictated by properties of the signal and the
environment. The signal energy is weakened by geometric attenuation as well as
absorption by the medium. The temporal and spectral properties can be modified by
sound absorption, refraction, and interference from multi paths caused by reflections.
The path from the source to the receiver may be bent due to refraction. Besides
geometrical attenuation, the ground effect and turbulence are the most important
mechanisms to influence communication sounds for airborne acoustics and bottom and
surface effects for underwater sounds. Refraction becomes very important close to
shadow zones. For echolocation signals, geometric attenuation and sound absorption
have the largest effects on the signals.
Echolocation, Excess attenuation, Ground effect, Refraction,
Reverberation, Scattering, Sound absorption, Sound attenuation, Transmission
Department of Biology, University of Southern Denmark, Odense M, DK-5230, Denmark.